un-couple messaging between connections; use non-blocking io

owrx/connection.py

@@ -3,8 +3,10 @@ from owrx.source import DspManager, CpuUsageThread, SdrService, ClientRegistry
 from owrx.feature import FeatureDetector
 from owrx.version import openwebrx_version
 from owrx.bands import Bandplan
-import json
 from owrx.map import Map
+from multiprocessing import Queue
+import json
+import threading
 
 import logging
 
@@ -14,20 +16,29 @@ logger = logging.getLogger(__name__)
 class Client(object):
     def __init__(self, conn):
         self.conn = conn
+        self.multiprocessingPipe = Queue()
+
+        def mp_passthru():
+            run = True
+            while run:
+                try:
+                    data = self.multiprocessingPipe.get()
+                    self.protected_send(data)
+                except (EOFError, OSError):
+                    run = False
+
+        self.passThruThread = threading.Thread(target=mp_passthru)
+        self.passThruThread.start()
 
     def protected_send(self, data):
-        try:
+        self.conn.protected_send(data)
-            self.conn.send(data)
-        # these exception happen when the socket is closed
-        except OSError:
-            logger.exception("OSError while sending data")
-            self.close()
-        except ValueError:
-            logger.exception("ValueError while sending data")
-            self.close()
 
     def close(self):
         self.conn.close()
+        self.multiprocessingPipe.close()
+
+    def mp_send(self, data):
+        self.multiprocessingPipe.put(data, block=False)
 
 
 class OpenWebRxReceiverClient(Client):
@@ -171,10 +182,10 @@ class OpenWebRxReceiverClient(Client):
         self.protected_send({"type": "smeter", "value": level})
 
     def write_cpu_usage(self, usage):
-        self.protected_send({"type": "cpuusage", "value": usage})
+        self.mp_send({"type": "cpuusage", "value": usage})
 
     def write_clients(self, clients):
-        self.protected_send({"type": "clients", "value": clients})
+        self.mp_send({"type": "clients", "value": clients})
 
     def write_secondary_fft(self, data):
         self.protected_send(bytes([0x03]) + data)
@@ -227,7 +238,7 @@ class MapConnection(Client):
         self.protected_send({"type": "config", "value": cfg})
 
     def write_update(self, update):
-        self.protected_send({"type": "update", "value": update})
+        self.mp_send({"type": "update", "value": update})
 
 
 class WebSocketMessageHandler(object):
@@ -289,3 +300,7 @@ class WebSocketMessageHandler(object):
 
     def handleBinaryMessage(self, conn, data):
         logger.error("unsupported binary message, discarding")
+
+    def handleClose(self):
+        if self.client:
+            self.client.close()

owrx/websocket.py

@@ -3,6 +3,7 @@ import hashlib
 import json
 import os
 import select
+import threading
 
 import logging
 
@@ -16,9 +17,11 @@ class IncompleteRead(Exception):
 class WebSocketConnection(object):
     def __init__(self, handler, messageHandler):
         self.handler = handler
+        self.handler.connection.setblocking(0)
         self.messageHandler = messageHandler
         (self.interruptPipeRecv, self.interruptPipeSend) = os.pipe()
         self.open = True
+        self.sendLock = threading.Lock()
         my_headers = self.handler.headers.items()
         my_header_keys = list(map(lambda x: x[0], my_headers))
         h_key_exists = lambda x: my_header_keys.count(x)
@@ -79,28 +82,52 @@ class WebSocketConnection(object):
         else:
             header = self.get_header(len(data), 2)
             data_to_send = header + data
-        written = self.handler.wfile.write(data_to_send)
+
-        if written != len(data_to_send):
+        def chunks(l, n):
+            """Yield successive n-sized chunks from l."""
+            for i in range(0, len(l), n):
+                yield l[i : i + n]
+
+        with self.sendLock:
+            for chunk in chunks(data_to_send, 1024):
+                (_, write, _) = select.select([], [self.handler.wfile], [], 10)
+                if self.handler.wfile in write:
+                    written = self.handler.wfile.write(chunk)
+                    if written != len(chunk):
                         logger.error("incomplete write! closing socket!")
                         self.close()
                 else:
-            self.handler.wfile.flush()
+                    logger.debug("socket not returned from select; closing")
+                    self.close()
 
     def protected_read(self, num):
         data = self.handler.rfile.read(num)
-        if len(data) != num:
+        if data is None or len(data) != num:
             raise IncompleteRead()
         return data
 
+    def protected_send(self, data):
+        try:
+            self.send(data)
+        # these exception happen when the socket is closed
+        except OSError:
+            logger.exception("OSError while writing data")
+            self.close()
+        except ValueError:
+            logger.exception("ValueError while writing data")
+            self.close()
+
     def interrupt(self):
         os.write(self.interruptPipeSend, bytes(0x00))
 
     def read_loop(self):
         self.open = True
         while self.open:
-            try:
             (read, _, _) = select.select([self.interruptPipeRecv, self.handler.rfile], [], [])
-                if read[0] == self.handler.rfile:
+            if self.handler.rfile in read:
+                available = True
+                while available:
+                    try:
                         header = self.protected_read(2)
                         opcode = header[0] & 0x0F
                         length = header[1] & 0x7F
@@ -124,8 +151,11 @@ class WebSocketConnection(object):
                         else:
                             logger.warning("unsupported opcode: {0}".format(opcode))
                     except IncompleteRead:
-                logger.warning("incomplete websocket read; closing socket")
+                        available = False
-                self.open = False
+
+        logger.debug("websocket loop ended; shutting down")
+
+        self.messageHandler.handleClose()
 
         logger.debug("websocket loop ended; sending close frame")